1. Field of the Invention
The present invention relates to a production process for a self-dispersible pigment, a self-dispersible pigment, an ink, an ink cartridge and an ink jet recording method.
2. Description of the Related Art
A self-dispersible pigment is mainly produced by a chemical pigment-modifying technology. For example, Japanese Patent Application Laid-Open No. H10-510861 describes a process for obtaining a self-dispersible pigment by causing a pigment to react with a diazonium salt. In addition, Japanese Patent Application Laid-Open No. 2012-528917 describes a process for obtaining a self-dispersible pigment by subjecting a carbonyl group on a particle surface of a pigment and a hydrazine compound to a condensation reaction.
However, the conventional pigment-modifying technologies have not satisfied a production process with high safety and reaction efficiency taking environmental burdens which have been regarded as important in recent years into consideration. In, for example, the production process described in Japanese Patent Application Laid-Open No. H10-510861, a nitrite low in stability and the like is utilized. In addition, residue of the nitrite and a nitrogen oxide may occur in some cases in the process of treating a pigment with a diazonium salt. Further, reaction efficiency is hard to be improved due to bubbles generated during reaction. In addition, the production process described in Japanese Patent Application Laid-Open No. 2012-528917 has involved a problem that reaction efficiency is low due to influence of the number of groups present on the particle surface of the pigment and reactivity thereof.